11720-L Welch Allyn 3.5V Coaxial Ophthalmoscope HeadWelch Allyn 3. 5V Coaxial Ophthalmoscope Head #11720 L This opthalmoscope head features easier entry into the eye, a larger field of view and reduced glare thanks to the patented Welch Allyn Coaxial Vision System. The halogen lamp insures true tissue color. This opthalmoscope has 18 unique aperture filter combinations and a Polarizing filter which virtually eliminates corneal reflection. Opthalmoscope head Halogen HPX lamp True tissue color 18 unique